Embedded system Development (i)--characters commonly used character processing function

Character processing is very common in C languages. We often need to convert information from a string form to internal data, or to a reverse conversion. How to implement these common operations efficiently?

Here are some of the methods I use most often. In the header file, add the following:

1#include"Ftypes.h"2 3 externu8_tConst__ascinfotbl[ the];4 5 Staticinline bool_t Ishexchar (u8_t c) {6c =__ascinfotbl[c];7   return(C &0x01) !=0);8 }9 Ten Staticinline bool_t Isnumericchar (u8_t c) { Onec =__ascinfotbl[c]; A   return(c = =0x01); - } -  the Staticinline bool_t Isalphabetchar (u8_t c) { -c =__ascinfotbl[c]; -   return(C &0x02) !=0); - } +  - Staticinline bool_t Isuppercasealphabetchar (u8_t c) { +c =__ascinfotbl[c]; A   return(C &0x06) ==0x02); at } -  - Staticinline bool_t Islowercasealphabetchar (u8_t c) { -c =__ascinfotbl[c]; -   return(C &0x06) ==0x06); -}

Then add the following in the C file:

u8_tConst__ascinfotbl[ the] = {  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,   0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,   0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,   0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,   0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,   0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,   0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01,   0x01,0x01,0x00,0x00,0x00,0x00,0x00,0x00,   0x00,0x03,0x03,0x03,0x03,0x03,0x03,0x02,   0x02,0x02,0x02,0x02,0x02,0x02,0x02,0x02,   0x02,0x02,0x02,0x02,0x02,0x02,0x02,0x02,   0x02,0x02,0x02,0x00,0x00,0x00,0x00,0x00,   0x00,0x07,0x07,0x07,0x07,0x07,0x07,0x06,   0x06,0x06,0x06,0x06,0x06,0x06,0x06,0x06,   0x06,0x06,0x06,0x06,0x06,0x06,0x06,0x06,   0x06,0x06,0x06,0x00,0x00,0x00,0x00,0x00,   0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,   0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,   0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,   0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,   0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,   0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,   0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,   0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,   0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,   0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,   0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,   0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,   0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,   0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,   0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,   0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, };

5 commonly used character information query functions are provided in the header file, defined by inline (inline). Note that the header file is included with the C file and is contained by more than one C file. Therefore, you should add static before the inline function defined by the header file to qualify the scope of the function.

• Static inline bool_t Ishexchar (u8_t c);

The query for the given character C is not a hexadecimal digit character. Hexadecimal characters include: ' 0 ' to ' 9 ', ' a ' to ' f ' (or lowercase ' a ' to ' F ').

• Static inline bool_t Isnumericchar (u8_t c);

The query for the given character C is not a decimal digit character. Decimal characters include: ' 0 ' to ' 9 '.

• Static inline bool_t Isalphabetchar (u8_t c);

Query for a given character C is not a letter (including uppercase and lowercase). The letters include: ' A ' to ' Z ', (or lowercase ' a ' to ' Z ').

• Static inline bool_t Isuppercasealphabetchar (u8_t c);

The query for the given character C is not an uppercase letter. The letters include: ' A ' to ' Z '.

• Static inline bool_t Islowercasealphabetchar (u8_t c);

Query for the given character C is not a lowercase letter. The letters include: ' A ' to ' Z '.

Through the implementation of these 5 basic character query function functions, we can realize that many similar functions and extensions can be realized by looking up the table! I have a lot of space to do with the application of the checklist.

Embedded system Development (i)--characters commonly used character processing function